Adapter coil



July 5,

Y E. c. RODMAN ADAPTER COIL Filed Oot 9. 1925 2 Sheets-Shea?I l zz/enzzo E (SHOCK/72am, eceaed,

A I'TORNEY July 59 l E. C. RODMAN AbAPTER COIL Filed Oct. 9 1925 2 Sheets-Sheet 2 ATTORN EY Patented July 5, 1927.

^ UNITED STATES PATENT OFFICE.

EARL C. RODMAN, DECEASED, LATE OFl TUSCOLA, ILLINOIS; BY BLANCHE RODMAN,

ADMINISTRATRIX, OF TUSCOLA,

ILLINOIS.

ADAPTER COIL.

This invention relates/to coils, and more particularly to a-'coil especially adapted 'tor use in telephony. v

One of the main objects of the invention is to provide a coil so constructed as to be readily connected to a switchboard ofl the magneto type, this coil when properly connected rendering it possible to convert the magneto type ofV switch board and exchange into common battery service without necessitating any material changes in the switch boardor exchange. A further object is to provide a. coil of this character of comparatively simple and inexpensive construction, the various elements of which are so arranged and related as to enable the coil to be readily connected to a source oi electrical energy, such` as a storage battery, a. telephone instrument Vand the switch board in such manner that' energy from the batte-ry can be utilizedl for energizing the telephone instrument andV also for energizing the switch board apparatus- Further objects will appear Jfrom the detailed description.

In the drawings: Fig. l is a diagram showing the coil as applied to a switch board of known type. Fig. 2 is a section'through-the coil casing, the coil being shown in elevation.

Fig. 3 is a diagram of the connections of the windings of the coil.

Fig. 4 is an enlarged lapping outer end portions of laminations of the core.'

Fig. 5 is a 'fragmentary sectional view through the heady and the upper portion of the coil casing.

detailof the oversome of .the

The coil is constructed in two sections each section being wound on a fiber spool l. Each section of the'coil is formedv of two windings, these windings being wound simultaneously and similarly. `In the coil illustrated, which is'intended for use in connection with a Q4 volt storage battery, the windings are formed of 1500 turns each of 29 gauge (B. & S.) enamelled copper wire, each winding of each section being formed of 750 turns. The windings are all wound simi- 1 larly. The spools l are mounted upona core Zv formed of strips of soft'iron, this core being 6". The remaining two of laminated construction. One half of the strips of the core are bent aboutl the outer portions oi' the spools with their ends overlapping, the ends of the outermost strips being secured together in any suitable manner so as to confine the other strips in posi-` tion. The other half of the strips are simllarly bent in the opposite direction. This provides, in effect, a shellv type of core ofV laminated construction which extends through andy enclosesfthe windings of the sections of the coil so as to electually conserve the energy induced in the' coil and obtain a close Vmagnetic coupling between the windingsof the coil.

Referring to the diagram (Figure 3) one winding ot the coil is formed in two sections 3 and 3a, the outside-end oi' section 3 being connected directly to the inside end of section 3a so that these two sections, in effect, forma single winding. The outer end 4 of section 3 and the outer end 4? of section 3a are intended to be connected to a switchboard in a manner to be described. The Vother winding of the coil is .formed of two sections 5- and 6 which a-rerelectrically insulated from each other. The outside end @tot section 6 and the outer end 5a of section 5 are. intended to be connectedA to an electric battery in amanner to be described. The

-from the battery and connected tothe switch board. v

In practice, after the coil has been properly assembled, it is placed in a suitable casing-,7 i-n the upper end of which is secured a wooden closure member or head 8. Six soldering lugs'f) aresecured inthe head S and are connected to the respective terminals of the coil sections. yTwo of these'lugs adjacent which are the letters SWB.r are connected to the terminals 4 and 4a. rFhe lugs marked L are connected to the two terminals 5 and lugs are connected to the opposite sides of the battery. In Fig` ure 3 I have shown` terminal 6il connected to the negative side of battery B and terminal 5a connected to the positive side ot the battery, though these connections can be reversed without affecting the operation of the coil.

ln Figure l l have indicated the manner common battery or central energy exchanges.

The poles ot battery B are connected to the two remaining lugs, as illustrated, and the positive pole of the battery is preferably grounded at l2. This groundin r ot the battery is not necessary but is prererred as serving to drain oli' static charges and also as preventing, to a considerable extent, cross talk between the wires. Wlhile l have illustrated but a single coil in connection with the switch board, there can be mounted any number of coils on a rack either on or adjacent the switch board, these coils being connected in the manner described to the individual lines, thus providing simple and eilicient means whereby a magneto exchange can be readily converted to a central energy or common battery.A

W ith the connections 'illustrated in Figure 3, when the receiver' is lifted from the hook ot the telephone instrument T, the circuit or' battery B is closed and thereV is an instantaneous rush ol' current through sections 5 and 6 of the right hand winding of the coil as considered in Figure 3, these sections being connected in series with the battery and with th-e telephone instrument. This rush of current induces a current in sections 3 and 3 ot the le't't hand winding of the coil, this induced current flowing through the wires 10 and energizing the coil of the annunciator or drop of the switch board thus releasing the shutter which drops and calls the operators attention to the tact that this circuit has been closed. To con- `nect the calling' party of the instrument T with the called party, the operator inserts a jack plug into the jack d thus breaking the annunciator circuit and connecting the wires l0 to the instrument of the party called. f During. use of the telephone T the vibrations of the diaphragm of the transmitter `of the instrument will generate Ya fluctuating current in sections 5 and 6 of the right hand winding of the coil, as considered in Figure 3. This will induce a similar fluctuating current in the sections 3 and 3 'of the right hand winding, which sections are connected in series with the wires l0 and, by means of the jack plug, to the instrument ot the party called. lnthis inanner, the battery B produces energy which is utilized directly to energize the transmitter of the instrument T and also, by induction, produces the energy which is utilized for transmitting the message over the wires l0. ln the event that the party at thetelephone T is called, the operator by inserting Vthe jack plug into the jack J connects the wires 10 in series with the calling party and the fluctuating or alternating current which is caused toy iiow through sections 3 and 3a of the coil winding by operation of the buzzer or other signalling device lat the switch board, will induce a similar current in sections 5 and 6 of the other winding thus operating the buzzer or bell of the telephone instrument T. When the receiver of this instrument is lifted trom'it-s hook the circuit is closed and conversation between theV the jack J and the drop D are all standard equipment and well known in this art and need not be further illustrated or described in detail. i

What l claim is:

l. In the combination Vwith a jack and drop et a telephone switchboard, a coil having two windings, the primary winding of said coil being continuous and connecting with said jack and drop, the secondary oit said coil divided into two sections, an outer end ot one of said sections communicating with a telephone instrument, the inner end of the same section communicating with a source of electrical energy, the corresponding end ot the opposite section connecting with the other pole of source ot said electrical energy and' the outer end otY the opposite section communicating with the aforesaid telephone instrument..

2. Tn combination with a jack and drop .i

switchboard oi' a telephoney instrument, a source of electrical energy, a coil ot two lateral simultaneous windings, the primaryV of said coil being continuous and communieating with thesaid yack and drop, and the Vsecondary of said coil being divided into two sections, the outer end of Vone of said sections and the inner end ofthe oppositeV section communicating with the said telephone instrument, and the outer end of the last named section and inner end ofthe opposite section to it connecting with the said Vsource of electrical energy, saidV coil being wound around a core of laminated overlapping metallic strips. Y y

. 8. In combination with a jack and drop switchboard, a telephone instrument, a source of electrical energy, and a coil of two lateral simultaneous windings, the primary oit said coil being continuous and `connnunicating with said jack and drop, the secondary of said coil being divided into two sections, connection between the outer end of one Seetion and the inner end of the opposite seetion with the said telephone instrument, a connection between the outer end of the last mentioned section and the inner end of the opposite section to it with a source of electrical energy7 said coil containing a laminated metal core and being mounted in a easing with the described terminals or end protruding therefrom. v

In testimony whereof I aix my signature.

f BLANCHE RODMA-N, Administratif/Vim of Earl 0. Rodman, deceased. 

